INFORM – Client is requesting network configuration
parameters but not an IP address

NAK – Server does not acknowledge a client's request
to use a previously used IP address

ICMP_ECHO – Server detects potential IP address is already
in use by another host.

BOOTP relay transactions include:

RELAY-CLNT – Message being relayed from the DHCP client
to a DHCP server

RELAY–SRVR – Message being relayed from the DHCP
server to the DHCP client

Transaction logging is disabled by default. When enabled, transaction
logging uses the local0syslog facility
by default. DHCP transaction messages are generated with a syslog severity level of notice, so by default,
transactions are logged to the file where other notices are logged. However,
because they use a local facility, the transaction messages can be logged
separately from other notices if you edit the syslog.conf
file to specify a separate log file.